Activation of periodate by chalcopyrite for efficient degradation of tetracycline hydrochloride

Activation of periodate (PI) has been widely recognized as an efficient and economical technique for the elimination of contaminants. In this study, a novel system with PI triggered by chalcopyrite (CuFeS2) was applied in the decomposition of tetracycline hydrochloride (TC). Effects of CuFeS2 dosage, PI concentration, pH value, inorganic anions, valence state change of Iodine ions (I-) were tested. The experimental findings demonstrated that the CuFeS2/PI system could successfully decompose TC in water under mild alkaline conditions (89.5 %, pH = 8). Compared with the other catalysts and the other CuFeS2/peroxide systems, CuFeS2/PI system exhibited more superior decontamination performance. Involvement of multiple reactive oxygen species such as superoxide radical (·O2–), hydroxyl radical (*OH) and singlet oxygen (1O2) in TC decomposition was confirmed by Electron spin resonance (ESR) tests and quenching experiment, and the interactions between Cu(Ⅱ)/Fe(III) and Cu(I)/Fe(Ⅱ) was confirmed. Based on a calculation using the density functional theory (DFT), the active sites of CuFeS2 for PI activation were revealed. Additionally, the analysis of degradation intermediates was conducted, with the toxicity of the intermediates analyzed. The CuFeS2/PI system was then applied in the treatment of real water samples, and the reusability of CuFeS2 was also investigated. This research presents a novel strategy as well as a theoretical foundation for CuFeS2 triggered PI to remove antibiotic contaminants.